In an article in the Federal Register, Vol. 45, No. 196, Oct. 7, 1980, entitled "Ozone-Depleting Chlorofluorocarbons; Proposed Production Restriction" by the Environmental Protection Agency, it is indicated that the amount of chlorofluorocarbons (CFC) emissions is of great concern to the environment, particularly with respect to its potential for ozone depletion. The problem is of such potential significance that even the banning of CFC has been considered.
CFSs are synthetic compounds which were developed in the 1930's. They are stable, non-flammable, and relatively non-toxic, which make them highly desirable from a worker and consumer safety standpoint. They are used in many applications because of their energy efficiency. Major CFC uses include use in air conditioning and refrigeration circuits, as well as for the freezing of foods.
Quite apart from future growth in the economy and in the refrigeration industry, CFCs currently have an immense economic impact on the U.S. economy, and the industry provides a substantial work force. Thus, on statistics presently available, about 500 million dollars worth of CFCs are used annually; more than 780 thousand jobs are directly related to CFC usage; approximately 260 thousand domestic businesses, mostly small businesses, use CFCs; the total value of goods and services that depend on CFCs exceed 28 billion dollars annually; the installed value of products that use CFCs is more than 135 billion dollars. In addition, CFCs are the basis of a major U.S. export market that would be jeopardized by restrictions on CFC usage because of emissions (leakage) of CFCs.
One of the major problems in existence relating to the use of CFCs is the leakage of the CFCs from refrigeration and air conditioning units. It can be easily seen that if restrictions were imposed because of such leakage, the impact on the economy would be enormous. However, even without a ban on the use of CFCs, a substantial economic loss is caused by the leakage and consequent replacement of CFCs in air conditioning and refrigeration systems. Moreover, there is a further economic loss because of additional demand of electrical energy caused by inefficient operation of cooling and refrigeration systems from which CFCs have leaked and have not been replaced. In this latter regard it has been estimated that if CFCs were banned, the adverse energy impact, caused by the inefficient operation of refrigeration and air conditioning units, would be equivalent to nearly 240 million barrels of oil by 1990, a figure which constitutes about 45% of current annual production from Alaska's North slope, or about 10% of the total United States crude oil imports in 1978.
In addition to the problems caused by refrigerant leakage as noted above, there are other known disadvantages including the inconvenience and cost of replacing refrigerant from a circuit from which it has already leaked. These problems exist not only relative to the use of CFCs as refrigerants, but also to all other refrigerant fluids. It is, accordingly, clear that it would be desirable to eliminate leakage of refrigerant fluids from air conditioning and refrigeration systems.
It should be understood that many difficulties in refrigerating and air conditioning circuits can be traced to the presence of moisture in the system. Moisture, usually considered acceptable in the art if present in quantities less than 5-25 parts per million, causes many problems as it circulates through the circuit in the presence of oil and the refrigerant, particularly at high temperatures which may be reached in the compressor and condensor. Thus, moisture may freeze at the refrigerant control orifice, causing clogging. Indeed, if moisture is present in large enough quantities, it will form ice in capillary tubes and expansion valves, plugging them. Water may also cause chemical breakdown of the oil, refrigerant and motor winding insulation and may create acids which ruin the motor winding and cause rusting or corrosion of the circuit walls, thereby causing pinholes and refrigerant leakage. It has been estimated that approximately 80% of all problems requiring air conditioning and refrigeration repairs are traceable to the presence of small quantities of moisture in the circuit.
To solve the difficulties caused by excess moisture, it is conventional to provide solid dehydrators or dryers in air conditioning and refrigeration circuits in the form of canisters, cartridges, filter units and the like. These devices, of course, increase the cost and complexity of the systems.
The 1940 U.S. Pat. No. 2,185,332 in the name of Crampton broadly discloses the addition of an acid neutralizing dehydrating agent, such as a metallic alcoholate, to an organic halogenated refrigerant fluid, such as dichloro, difluoro methane, in order to remove moisture from and neutralize any acid which may be either initially present in the refrigerant or subsequently formed during its use. However, there are many problems inherent in the use of alcoholates as suggested by Crampton.
Thus, the preferred alcoholate of Crampton is sodium methylate which is a white, free-flowing powder, sensitive to oxygen and which decomposes in air above 260.degree. F. It is a hazardous material, flammable when exposed to heat or flame, and toxic and corrosive to tissue.
The next alcoholate in the series, sodium ethylate, is a white powder which readily hydrolyzes to alcohol and sodium hydroxide. It too is hazardous and forms sodium hydroxide when exposed to moisture. Another alcoholate mentioned, sodium phenolate, comprises white, deliquescent crystals which are decomposed by carbon dioxide in the air; this material also is hazardous, being a strong irritant to skin and tissue.
In addition to being hazardous materials, the alcoholates have other disadvantages. As pointed out by Crampton (page 2, line 60), sodium methylate reacts to form sodium chloride, which can precipitate in the system and cause blockage and corrosion. In addition, sodium methylate reacts with water to form sodium hydroxide, another corrosive material (page 3, line 5 of Crampton).
Moreover, regardless of the hazardous and corrosive nature of the products themselves and some of their products of reaction, the alcoholates themselves are solid and are usable according to the Crampton disclosure only because they are dissolved in solution. This presents an additional inherent disadvantage in that localized conditions may exist in the refrigeration circuit which cause the solid particles to come out of solution and deposit, possibly causing blockage and/or corrosion.